feat: add a feature to statically disable debugging in the sdk

When the debug feature is disabled, most actor debugging logic should
get statically compiled out.

I've left it enabled by default for now, but we should consider
disabling it by default for the final release. But if we do that, we
need _some_ way to re-execute actors with debugging enabled.

Author: Stebalien

sdk/Cargo.toml

@@ -15,7 +15,11 @@ cid = { version = "0.8.2", default-features = false }
 fvm_shared = { version = "0.5.1", path = "../shared" }
 ## num-traits; disabling default features makes it play nice with no_std.
 num-traits = { version = "0.2.14", default-features = false }
-lazy_static = "1.4.0"
+lazy_static = { version = "1.4.0", optional = true }
 log = "0.4.14"
 thiserror = "1.0.30"
 fvm_ipld_encoding = { version = "0.1", path = "../ipld/encoding" }
+
+[features]
+default = ["debug"]
+debug = ["lazy_static"]

sdk/src/debug.rs

@@ -1,47 +1,64 @@
-use lazy_static::lazy_static;
+pub use inner::*;
 
-use crate::sys;
+#[cfg(not(feature = "debug"))]
+mod inner {
+    #[inline(always)]
+    pub fn init_logging() {}
 
-lazy_static! {
-    /// Lazily memoizes if debug mode is enabled.
-    static ref DEBUG_ENABLED: bool = unsafe { sys::debug::enabled().unwrap() >= 0 };
-}
-
-/// Logs a message on the node.
-#[inline]
-pub fn log(msg: String) {
-    unsafe {
-        sys::debug::log(msg.as_ptr(), msg.len() as u32).unwrap();
+    #[inline(always)]
+    pub fn enabled() {
+        false
     }
+    #[inline(always)]
+    pub fn log(_: String) {}
 }
 
-/// Returns whether debug mode is enabled.
-#[inline(always)]
-fn enabled() -> bool {
-    *DEBUG_ENABLED
-}
+#[cfg(feature = "debug")]
+mod inner {
+    use lazy_static::lazy_static;
 
-/// Logger is a debug-only logger that uses the FVM syscalls.
-pub struct Logger;
+    use crate::sys;
 
-impl log::Log for Logger {
-    fn enabled(&self, _: &log::Metadata) -> bool {
-        // TODO: per-level?
-        enabled()
+    lazy_static! {
+        /// Lazily memoizes if debug mode is enabled.
+        static ref DEBUG_ENABLED: bool = unsafe { sys::debug::enabled().unwrap() >= 0 };
     }
 
-    fn log(&self, record: &log::Record) {
+    /// Logs a message on the node.
+    #[inline]
+    pub fn log(msg: String) {
+        unsafe {
+            sys::debug::log(msg.as_ptr(), msg.len() as u32).unwrap();
+        }
+    }
+    /// Initialize logging if debuggig is enabled.
+    pub fn init_logging() {
         if enabled() {
-            log(format!("[{}] {}", record.level(), record.args()));
+            log::set_logger(&Logger).expect("failed to enable logging");
         }
     }
 
-    fn flush(&self) {}
-}
+    /// Returns whether debug mode is enabled.
+    #[inline(always)]
+    pub fn enabled() -> bool {
+        *DEBUG_ENABLED
+    }
+
+    /// Logger is a debug-only logger that uses the FVM syscalls.
+    struct Logger;
+
+    impl log::Log for Logger {
+        fn enabled(&self, _: &log::Metadata) -> bool {
+            // TODO: per-level?
+            enabled()
+        }
+
+        fn log(&self, record: &log::Record) {
+            if enabled() {
+                log(format!("[{}] {}", record.level(), record.args()));
+            }
+        }
 
-/// Initialize logging if debuggig is enabled.
-pub fn init_logging() {
-    if enabled() {
-        log::set_logger(&Logger).expect("failed to enable logging");
+        fn flush(&self) {}
     }
 }

sdk/src/sys/mod.rs

@@ -4,7 +4,7 @@ pub use fvm_shared::sys::TokenAmount;
 
 pub mod actor;
 pub mod crypto;
-//#[cfg(feature = "debug")]
+#[cfg(feature = "debug")]
 pub mod debug;
 pub mod gas;
 pub mod ipld;